Apparatus for producing filamentary or sheetlike material of plural components

ABSTRACT

An extrusion apparatus for producing synthetic sheet material in which a plurality of extrudable synthetic materials are extruded as interspersed streams through alternating groups of extrusion orifices arranged in a row and collected into a coherent assembly within a collecting chamber having an outlet orifice slot therein for removal of the thus formed coherent assembly, combing means being provided to draw out threads of the materials from the interspersed streams thereof on at least certain surfaces of the coherent assembly. Preferably an array of spaced-apart wedgeshaped elements are arranged in gridlike manner between the row of orifices and the collecting chamber and a relative movement generally transverse to the extrusion direction is imparted to such an array in order to subdivide the interspersed streams into thin lamellae of the extrudable materials. One ore more of the edges of such wedge-shaped elements can be serrated in order to draw out threads from the lamellae passing in contact therewith and the relative movement of the array serves to interconnect the thus drawn out threads and bond the lamellae together.

United States Patent [72] Inventor Ole-Bendt Rasmussen 28, Rugmarken,Farum, Denmark [21] Appl. No. 871,305 [22] Filed Dec. 9, 1969 [45]Patented Jan. 4, 1972 [32] Priority June 8, 1965 [33] Great Britain [31]24,068/65 Original application June 7, 1966, Ser. No. 555,835, nowPatent No. 3,505,162. Divided and this application Dec. 9, 1969, Ser.No. 871,305

[54] APPARATUS FOR PRODUCING FILAMENTARY 0R SHEETLIKE MATERIAL 0F PLURALCOMPONENTS 10 Claims, 13 Drawing Figs.

[52] US. Cl 425/464, 264/75, 264/171 [51] Int. Cl B29f 3/00, B29f 3/12[50] Field of Search 18/13 D, 13 F, 13.1, 13 K, 13 N, 13 P, 13 R, 13 RR;264/75, 171, 172, 175

[5 6] References Cited UNITED STATES PATENTS 3,511,742 5/1970 Rasmussen161/109 IXIII Orsini ABSTRACT: An extrusion apparatus for producingsynthetic sheet material in which a plurality of extrudable syntheticmaterials are extruded as interspersed streams through alternatinggroups of extrusion orifices arranged in a row and collected into acoherent assembly within a collecting chamber having an outlet orificeslot therein for removal of the thus formed coherent assembly, combingmeans being provided to draw out threads of the materials from theinterspersed streams thereof on at least certain surfaces of thecoherent assembly. Preferably an array of spaced-apart wedge-shapedelements are arranged in gridlike manner between the row of orifices andthe collecting chamber and a relative movement generally transverse tothe extrusion direction is imparted to such an array in order tosubdivide the interspersed streams into thin lamellae of the extrudablematerials. One ore more of the edges of such wedge-shaped elements canbe serrated in order to draw out threads from the lamellae passing incontact therewith and the relative movement of the array serves tointerconnect the thus drawn out threads and bond the lamellae together.

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APPARATUS FOR PRODUCING FILAMENTARY OR SI'IEETLIKEMATERIAL OF PLURALCOMPONENTS This application is a division of Ser. No. 555,835, now U.S.Pat. No. 3,505,162, filed June 7, 1966.

In the past it has apparently always been assumed that one can onlyproduce materials having the characteristics necessary of textiles bybuilding these materials up from small elements which are generallyfibers or threads. I have now found that it is not necessary to startfrom these small elements in order to obtain a textile material.

This application is concerned with an extrusion apparatus for producinga class of materials that have a wide variety of uses. The materialsaccording to the invention may be used as textiles, for example asclothing. Other materials may be used as carpeting. Yet other materialsmay be used as packaging, yet others may be used as building boardswhile yet others may be leatherlike. The materials according to theinvention may be sheetlike or filamentary. If filamentary they maysubsequently be formed into any of the products that can be formed frommore usual types of filaments.

A filamentary or sheetlike material according to the invention is formedof particles of synthetic polymeric material and each having a spine anda plurality of tentacles which are of the same materials as the spineand are drawn out from the spine and which lie substantially along aflat dimension of the sheetlike material or along the length of thefilamentary material, the particles being held together by the tentaclesfrom one particle bonding with adjacent particles.

A convenient method of making the sheetlike or filamentary materialaccording to the invention comprises forming by extrusion fluid orsemifluid substantially lamellaeshaped particles of polymeric materialseparated by a second fluid or semifluid component and arranged in athin structure, drawing tentacles out from the particles and bonding thetentacles from one particle with other particles to form the shape ofthe desired filamentary or sheetlike material, setting the polymericmaterial of the particles and destroying the continuous structure of thesecond component.

The particles in the filamentary or sheetlike materials according to theinvention may have one of a variety of shapes. The tentacles may bedrawn out from the sides of the spines of the particles or they mayextend from central parts of the spine.

The basic idea behind the invention is the drawing out from particles ofsynthetic material of tentacles that are subsequently used to bond thefilamentary or sheetlike materials together. Depending upon the shape ofthe initial particles and upon the extent to which tentacles are drawnout from the particles and upon the places on the particles from whichthe tentacles are drawn out so will the shape of the spine of eachparticle be determined. Often the spines are lamellae, that is to saythe thickness of each is substantially less than either of its otherdimensions. However, it often happens that one may draw out from theparticles tentacles to such an extent that one can no longer considerthe spines as lamellae shaped but they may instead be rod shaped. Thusthe spines may have two of their dimensions similar and the thirddimension much greater than the other two. Whatever the basic shape ofthe spines the spines generally will not be arranged linearly in thematerial. For example, lamellae may be arranged so that they have asaddle shape and rodshaped spines may be folded back on themselves.

The accompanying drawings serve to assist understanding of theinvention. In these drawings:

FIG. 1 is a diagrammatic representation of a typical material producedwith an apparatus according to this invention which is made up ofparallel rows of saddleshaped segments;

FIG. 2 is a view of apparatus suitable for making materials according tothe invention while FIG. 3 is a section on the line XIII-XIII of FIG. 2and FIG. 4 is a plan view of part of the apparatus shown on the lineXIVXIV of FIG. 2;

FIG. 5 is a view similar to that of FIG. 2 of a difi erent apparatus andFIG. 6 is a fragmentary section on the line XVI XVI in FIG. 5 showingonly the outlet chamber for that apparatus;

FIG. 7 is a view similar to that of FIG. 12 of yet another apparatus andFIG. 8 is a-fragmentary section on the line XVIIIXVIII of FIG. 7 showingthe outlet chamber for the apparatus of FIG. 7;

FIG. 9 is a section through an arrangement of ducts suitable forextruding the polymeric material and second component in the method ofthe invention;

FIG. 10 is a plan from above on the ducts shown in FIG. 9;

FIG. 11 is a modification of the apparatus shown in FIG. 6; and

FIG. 12 is a section through apparatus suitable for making filaments orsheet materials; and

FIG. 13 is a diagrammatic representation of a product includingtentacles extending from central parts of lamellae and made by modifiedforms of apparatus embodying features shown in FIGS. 9 and 1 1.

The tentacles drawn out from the spines of the particles of thematerials according to the invention are most usually fiberlike, andpart of the bonding at least generally results from the felting togetherof the fiberlike tentacles with one another. However, in addition tothis felting, or instead of this felting, there may also be bonding fromthe use of a suitable bonding agent. This bonding agent or some othermaterial that is present between adjacent particles (i.e. formed orsplit material as described in more detail below) may also assist in theholding together of the particles. In general, however, the

tentacles are always such that the particles can be held together bythem, with or without bonding agent, and that any bonding resulting frommaterial between adjacent particles and not associated with thetentacles merely serves to increase the strength of the product stillfurther.

In order that the sheet material shall be held together it is essentialthat sufiicient tentacles be drawn out from each particle. Satisfactorybonding will not occur if there is just one tentacle drawn out from eachside of each spine or if just two tentacles extend from central parts ofadjacent lamellaeshaped spines. Instead, there must be a plurality oftentacles from each spine, that is to say there must be at least threetentacles from each spine. As is shown in the drawings there aregenerally many more than this, especially when the tentacles are drawnout from the sides of the spines rather than the centers.

Basic methods and apparatus for extruding fluid or semifluidsubstantially lamellaeshaped particles of polymeric material separatedby a second fluid or semifluid component are known and are described inmy copending U.S. Pat. application Ser. No. 391,997, filed Aug. 25, 1964now US. Pat. No. 3,511,742. The basic process generally comprises theuse of a body in which there is a row of adjacent parallel ducts andmeans for supplying one molten material to alternate ducts and a secondcomponent to the remaining ducts in the row. The body is so shaped thatthe extruded material is in the form of a thin structure. In the processand apparatus of the present invention it is generally preferred toextrude the lamellae through a row of ducts as continuous lamellae. Therow may be circular and the lamellae, after extrusion, rotated relativeto the row in order that the lamellae become arranged helically into acylindrical sheet. This sheet may then be split along its length toprovide a flat sheet. In another method and apparatus the row oforifices is straight and the lamellaeshaped particles are extruded ascontinuous lamellae in a flat sheet and are then folded back over oneanother, thereby becoming arranged in zigzag fashion. Whatever themethod of extrusion the continuous lamellae may subsequently be cut intoshort lengths before the tentacles are drawn out from them.

The arrangement of the lamellae after extrusion into the desired patternin the sheet material is usually effected by subjecting the lamellae toa suitable lateral shear. Thus, they may be extruded through the ductsinto a chamber in which they are under pressure from one or moresurfaces that move relative to the ducts to provide the desired shear.Thus if the row of ducts to provide the desired shear. Thus if the rowof ducts is circular the one or more surfaces may rotate relative to theducts while if the row is linear then the one or more surfaces mayreciprocate relative to the ducts, thus dragging the lame]- late into azigzag pattern.

When the tentacles are to be drawn out from a side of each originallylamellaeshaped particle it is preferred to carry out the drawing in atleast two operations. If the particles, even though they are stillfluid, are merely dragged against a comb then it is not readily possibleto form tentacles that give really satisfactory bonding. Instead, it ispreferred to drag the side, or sides, of the lamellae from which thetentacles are to be drawn under pressure against a serrated edge andthen to drag the serrated surface so formed under pressure against aknife edge. This knife edge may be straight. The purpose of this seconddrawing step is to draw a tentacle out from the starting points providedby the first step, and so a comb is not required for the second step.If, as in some constructions, it is preferred or necessary that the edgeused for the second drawing step should be serrated it should beconstructed and used in such a manner that as far as possible the partsof the serrated surface to be drawn should come in contact with convexparts of the edge rather than concave. By carrying out the tentacledrawing in two stages more uniform tentacles and tentacles of greaterlength are obtained. The initial drawing against the serrated edgeprovides a serrated surface and the tentacles are subsequently drawn outfrom the ridges of this surface.

A suitable apparatus for carrying out the process of the invention isshown in FIGS 2 to 4 of the accompanying drawings. To the compositesheet extruding device the two melted polymers designated I and II aresupplied by means of two feeder extruders (not shown). I is used to formthe segments of the fabric and II is the second component. In thedrawing I is marked with shading lines, whereas II is not marked. Fromthe extruders, I and II are pressed into the device through mainchannels and subsequently divided out on a series of very narrow ducts13 and 14 separated by walls 12. Walls 12 separate ducts 13, throughwhich the polymeric material I is extruded, from ducts 14 through whichthe second component II is extruded. The main channel for supplyingpolymer I to ducts 13 is seen at II and a similar channel (not seen)communicates with ducts 14 for supplying the second component II toducts 14. The ducts 13 and 14 are shown here in simplified form, but areshown in greater detail in FIG. 9. There is an array of similar wedges15 spaced downstream from the orifices 16 of the ducts, each beingarranged with a comer edge 18 directed towards the orifices and theother two corner edges, 17, adjacent other wedges, being serrated. Thewhole assembly is within a narrow body, defined by walls 37, (see FIG.4) and this body also includes a necked down outlet chamber 19 forreceiving material extruded through the orifices and which has passedthrough the array of wedges, the chamber 19 facing towards the wedgesand having an elongated outlet slot 20 spanning the length of the row oforifices relative to the orifices. The array of wedges is adapted to begiven motion relative to the arrangement of orifices in a directiontransverse to the general direction by means not shown. They may resulteither in relative rotation or in relative reciprocation. Either thearray of the wedges or the ducts, or both, may be moved. The shearexerted by the edge 18 results in streams 21 of polymer I and streams 22of second component II being dragged across the top of the orifices.When the wedges reciprocate, the streams 21 and 22 are dragged back andforth. As further material is forced out through the ducts 13 and 14 thestreams are gradually forced up into contact with the edges 18 of thewedges and are chopped into short segments 23 by these edges. In orderto assist in the dragging and chopping, or tearing, of the streams theedges 18 are preferably finely serrated. The teeth on the edges 18 maybe, for example, 0.2 mm. apart. Preferably the distance between theedges l8 and the orifices 16 is greater than the distance between twoadjacent ducts 13 but is preferably less than the width of each duct 13.When the wedges are reciprocating the amplitude of the reciprocationsshould be many times greater than the distance between two adjacentducts 13. The duration of half a reciprocation should preferably beabout the same as the time taken for material extruded from an orifice16 to reach the edge 18. The edges 17 are coarsely serrated and theremay be, for example, about l millimeter between adjacent teeth.

The segments 23, some of which are shown in FIG. 2, are forced upthrough the passage between adjacent wedges 15. This passage is ofgradually decreasing width up to a restriction formed by opposedoverhanging shoulders, at which the passage width is substantially lessthan elsewhere along the length of the passage. In the apparatusillustrated the ends of both shoulders are defined by serrated edges 17,but if tentacles are only to be drawn out from one side it is sufficientfor one side only to be serrated. The segments 23 are then forced upfurther, past the neck, and are then drawn under pressure against areciprocating comb provided by the upper edge 24 of the wedges 15. Thiscomb serves not only to draw out further the tentacles, the drawing ofwhich was started by the serrated edges 17 but also to felt together thetentacles that are drawn out. The comb 24 reciprocates and so thesegments are arranged in a zigzag manner in parallel rows, the segmentsin each row being in endtoend relationship. The comb 24 is preferablyarranged so that the ridges formed on the lamellae by contact with theserrated edge 17 come into contact with the ridges of the comb 24,rather than with the recesses. Thus the ridges should be about 1millimeter apart.

The segments 23 drag against the edge surfaces along either side of thepassage formed between the two adjacent wedges l5 and so become saddleshaped, as seen in FIG. 1. If they drag also against the ends 25 of thepassage between adjacent wedges as defined by walls 37, then they willbecome cup shaped. In order to reduce this tendency, the length of thepassage, as defined by the ends 25, is preferably increased or expandedgradually towards the neck 17, and also further, up to the comb 24. Thereduction in width of the passage between each wedge up to therestriction not only ensures that the segments engage with the edge 17under pressure, but also produces a hangup of material.

Upon passage through the chamber 19 and outlet 20 the segments 23, whichby then have been felted together into rows, are forced into closercontact with one another and the bonding of the whole together isimproved. In addition to moving the wedges or the ducts, both may move,or the chamber wall may move, or all three may move.

The orifices 16 may be, for example, from 3 mm. to 2 cm. generally about8 mm. long, viewed as in FIG. 3 and may be, for example, about 0.3 mm.wide, viewed from FIG. 2. If the outlet 20 is suitably dimensioned withrespect to the width of the chamber 19 at the combs 24 then the segmentsare turned through during their passage through this chamber. The

outlet must be substantially narrower than the length of the segments,viewed in the direction of FIG. 3, for this to occur. A knife edge maybe provided in the outlet with the result that the serrated surface orsurfaces of the segments, resulting from contact with the comb 17, aredragged under pressure against this knife edge, tentacles thus beingdrawn out. In general, for a substantial number of the segments to beturned round, the outlet 20, viewed as in FIG. 3, should have a width offrom onethird to onefourth of the width of the widest part of thechamber 19. In practice generally some of the segments will be turnedround and others will not, some felting together resulting from theaction of the edge 24 and some from a knife edge in the outlet 20.

The apparatus shown in FIGS. 5 and 6 is similar to that shown in FIGS. 3to 4 except that the upper edges 24 of the wedges 15 is missing. Thisapparatus is intended primarily for processes in which the dimensions ofthe outlet 20 are such that the segments are turned through 90 as theypass through and out of the chamber 19 and accordingly the outlet 20 isprovided with a knife edge 26 to serve to draw out the tentacles.

The apparatus shown in FIG. 11 is a modification of that shown in FIG. 6as in this a barbed needle 27 is fitted to reciprocate within the outletso as to needle segments together as they pass through the outlet. Theneedle 27 is described in more detail below. This needle may have inaddition to its stitching movement a rotary movement to produce twist ofthe tentacles. The stitching movement is rapid and preferably at timeswhen the lateral movement of the fluid mass is comparatively slow. Asimilar needle arrangement may be provided in the outlet 20 shown inFIG. 3. It will be appreciated that the needle punching results intentacles being carried from one lamellae particle through needlepunchedholes in adjacent particles.

In FIGS. 7 and 8 there is shown apparatus suitable for use in a processin which the lamellae are not cut into short segments. In this apparatusthe wedges are omitted and the body comprises the ducts and neckeddownoutlet chamber 19 directed towards the orifices of the ducts and havingan elongated outlet slot 20 spanning the length of the row of ducts asbefore. The apparatus also includes means for moving the neckeddownoutlet chamber 19 along the row of orifices relative to the orifices. Toinitiate the drawing out of the tentacles there is a serrated edge 31 atthe entrance to the outlet 20 and a straight knife edge 28 at the exitto the outlet by the edge 31. There may also be edges 31 and 28 on theopposite side of the outlet. The edge 31 is preferably set in a channel29 in order that turbulence shall be at a minimum when the tentacles aredrawn out. Again, there is preferably a pocket 30 between the edges 31and 28, again to produce a hangup of material. Instead of drawingtentacles out by contact with the edges 31 and 28, or in addition tothis, the continuous lamellae may be needled together by needlesreciprocating up and down through the ducts.

A Preferred arrangement of ducts is shown in FIGS. 9 and 10. Needles areshown only in one side. The orifices 16 of the ducts 13 from which thepolymeric material of which the particles are to be composed is extrudedare preferably raised above the orifices 16 of the ducts 14, from whichthe second component is extruded. As a result of this the carrying ofthe polymer streams extruded from the ducts 13 over the ducts 14 isfacilitated. Preferably the orifices 16 both of ducts 13 and 14 arenarrower than the main parts of the ducts. Preferably the ducts 14 are alittle longer, when viewed from above, as in FIG. 10, than are the ducts13. The advantage of this is that the second component flows over thewalls 37 of the body defining the whole apparatus and which encloses thepolymer streams extruded from the ducts, and so acts as a lubricantbetween the polymer streams extruded from the ducts 13 and the walls.Preferably the distance apart of the ducts 13 is less than their width,as viewed from above. If a needle is to reciprocate through the ductsthen it is preferably arranged within the ducts 14, as shown. Theneedles 27 generally have sharp leading edges 38 to punch holes androunded trailing edges 39 to draw the tentacles out. Preferably theneedles rotate in order to produce a twist of tentacles. The stitchingcarried out rapidly and preferably at times when the lateral movement ofthe mass is comparatively slight.

It is preferred that the component from which the particles are to beformed should have a higher melt viscosity than the second component.This has the advantage that the second component serves as aparticularly satisfactory lubricant and also it facilitates the choppingand shaping of the particles of the polymer, since they are the moreviscous. As an example, the polymeric material of which the particlesare to be formed preferably has a melt viscosity of from 3 to 30 timesthe melt viscosity of the second component.

In FIG. 12 there is shown an apparatus suitable for making sheet orfilamentary material. It comprises a body including a pair of ducts 32and 33 separated by a wall 34 having a serrated leading edge 35. Thereis a gate 36 slidable over the orifices of the ducts to open one orificewhile closing the other. There are means (not shown) for reciprocatingthe gate over the orifices and means for supplying one polymericmaterial to duct 33 and the other component to duct 32. Thus, in thisapparatus pulses of the polymeric material and the second componentalternate with one another and a product is formed consisting of asingle row of the pulses. By appropriately choosing the rate ofextrusion and the rate of reciprocation of the gate, pulses of anydesired shape may be formed. Generally they will be substantiallylamellae shaped. If the ducts and gate are short or circular then afilament is formed. As a result of the gate sliding over the serratededge tentacles 37 are drawn out from the polymeric material by thesliding of the gate. In this apparatus the viscosity of the two fluidcomponents may be similar or they may be different.

This method of reciprocating a gate over ducts may be applied to theproduction of sheetlike materials made up of a number of rows ofsegments. Thus, the polymeric material may be fed through a number ofpolymer ducts arranged in a row while feeding the second componentthrough component ducts, repeatedly closing the polymer ducts whileopening the component ducts and vice versa, thereby forming a sheetcomprising parallel rows of saddleshaped segments of the polymericmaterials separated from one another by the second component, combingthe edges of the segments and entangling the tentacles of adjacentsegments together, setting the polymeric material of the segments andremoving or splitting into fibers the second component. The opening andclosing of the ducts may be effected by reciprocation of a series oftriangular wedges, moving with their bases over the orifices to theducts, and having a comb cut into their upper edge so as to serve tocomb the edges of adjacent rows and entangle the tentacles thus drawnout together.

Both the polymeric material and the other component extruded with thepolymeric material must be fluid or semifluid in order that they areextrudable. It is generally preferred that the polymeric material ofwhich the particles are formed should be of quite a soft polymer inorder to improve the properties of the final product, textile propertiesand the tear resistance at the junction of the tentacles with the spinebeing improved in particular. Suitable polymeric materials arepolyamides, polyesters, polyurethanes, polypropylene, polyethylene, andother crystalline polyolefines, polyvinyl chloride, generally slightlyplasticized, and extrudable copolymers of polvinylidene chloride,highimpactstrength modified polystyrene, and polycarbonates.Particularly preferred polymers are the polyamides known as nylon. Thepolymers may be extruded as prepolymers and subsequently polymerizedduring the process.

The second component must be one whose continuous structure can bedestroyed when desired. It can be of the same type of polymer as thepolymeric material of which the particles are fonned but of differentmolecular weight or it can be of a different polymeric material. It canbe a paste free of any polymeric material being, for example, a mixtureof a lubricant and a thickening agent. It is particularly preferred touse as all or part of the second component a polyoxyethylene resin, asthis is water soluble and can readily be removed by washing with water.Mixtures of the polymeric material of which the particles are formed andanother polymeric material or other material may be used as the secondcomponent.

For further details as to the materials employed in the apparatus of theinvention, reference may be had to US. Pat. No. 3,505,162 covering theproducts of this invention.

I claim:

1. An apparatus for the manufacture of a synthetic sheet material byextrusion comprising a multiplicity of extrusion orifices arranged in arow, means for supplying a first extrudable material to first set ofsaid orifices, means for supplying a second extrudable material to asecond set of said orifices alternating with the first set of orifices,a collecting chamber for combining interspersed streams of saidmaterials extruded through said orifices into a coherent assembly of amultiplicity of lamellae extending through a substantial extent of thethickness of said assembly, said collecting chamber including an outletslot generally coextensive in length with said row of orifices forremoving said coherent assembly from said chamber, and combing meanscontacting the extrudable materials after extrusion from said orificesbut before removal of the coherent assembly from the chamber for drawingout threads from said lamellae to bond said lamellae together.

2. The apparatus of claim 1 including an array of wedgeshaped elementsdisposed in spacedapart relation generally transversely of the extrusiondirection intermediate said row of orifices and said collecting chamberwith the apexes of said elements lying nearest said orifices, each ofsaid wedgeshaped elements having at least one edge thereof serrated toact as said combing means.

3. The apparatus of claim 2 wherein the apex of each wedgeshaped elementis serrated.

4. The apparatus of claim 2 wherein the mutually facing edges of eachadjacent pair of said wedgeshaped elements are serrated.

5. The apparatus of claim 2 wherein said wedgeshaped elements arediamondor doublewedgeshaped and the edges row of extrusion orifices andsaid collecting chamber and including means for imparting relativemovement to said array in said transverse direction.

7. The apparatus of claim 1 wherein said collecting chamber includes onat least one side thereof a row of teeth adjacent and parallel to theoutlet slot therefrom.

8. The apparatus of claim 7 wherein said outlet slot is formed with arestriction therein downstream of said row of teeth.

9. The apparatus of claim 7 wherein said collecting chamber is mountedfor movement in a direction generally transverse of the extrusiondirection relative to the row of extrusion orifices and including meansfor imparting said relative movement to said collecting chamber in saidtransverse direction.

10. The apparatus of claim 1 including a row of closely spacedreciprocable needles arranged generally parallel to the row of orificesand adapted to penetrate said interspersed streams of extrudablematerials in a direction generally parallel to the extrusion directionand means for reciprocating said needles.

1. An apparatus for the manufacture of a synthetic sheet material by extrusion comprising a multiplicity of extrusion orifices arranged in a row, means for supplying a first extrudable material to a first set of said orifices, means for supplying a second extrudable material to a second set of said orifices alternating with the first set of orifices, a collecting chamber for combining interspersed streams of said materials extruded through said orifices into a coherent assembly of a multiplicity of lamellae extending through a substantial extent of the thickness of said assembly, said collecting chamber including an outlet slot generally coextensive in length with said row of orifices for removing said coherent assembly from said chamber, and combing means contacting the extrudable materials after extrusion from said orifices but before removal of the coherent assembly from the chamber for drawing out threads from said lamellae to bond said lamellae together.
 2. The apparatus of claim 1 including an array of wedge-shaped elements disposed in spaced-apart relation generally transversely of the extrusion direction intermediate said row of orificEs and said collecting chamber with the apexes of said elements lying nearest said orifices, each of said wedge-shaped elements having at least one edge thereof serrated to act as said combing means.
 3. The apparatus of claim 2 wherein the apex of each wedge-shaped element is serrated.
 4. The apparatus of claim 2 wherein the mutually facing edges of each adjacent pair of said wedge-shaped elements are serrated.
 5. The apparatus of claim 2 wherein said wedge-shaped elements are diamond- or double-wedge-shaped and the edges thereof remote from said orifices is serrated.
 6. The apparatus of claim 2 wherein said array of wedge-shaped elements is mounted for movement in a direction generally transverse of the extrusion direction relative to said row of extrusion orifices and said collecting chamber and including means for imparting relative movement to said array in said transverse direction.
 7. The apparatus of claim 1 wherein said collecting chamber includes on at least one side thereof a row of teeth adjacent and parallel to the outlet slot therefrom.
 8. The apparatus of claim 7 wherein said outlet slot is formed with a restriction therein downstream of said row of teeth.
 9. The apparatus of claim 7 wherein said collecting chamber is mounted for movement in a direction generally transverse of the extrusion direction relative to the row of extrusion orifices and including means for imparting said relative movement to said collecting chamber in said transverse direction.
 10. The apparatus of claim 1 including a row of closely spaced reciprocable needles arranged generally parallel to the row of orifices and adapted to penetrate said interspersed streams of extrudable materials in a direction generally parallel to the extrusion direction and means for reciprocating said needles. 